Carbureter



A. Cox. v CARBURETER.-

APPLICATION FILED MAR. 1. I919.

i Patented Aug. 31,1920.

3 SHEETS-SHEET L.

A. COX.

CARBURETER. APPUCATION FILED MAR. 1. 1919.

Patented Aug. 31, 1920.

3 SHEETS-SHEET 2.

A. COX.

CARBU.RETER-.

APPLICATION FILED MAR. 1. 1919.

Patentd Aug. 31, 1920."

UNITED STATES PATENT OFFICE,

ARTHUR cox, or omon, NEAR BIRMINGHAM, ENGLAND.

CARB'URETERR Specification of Letters Patent.

Patented Aug. 31, 1920.

Application filed March 1, 1919. Serial No. 280,127.

To all whom it may concern:

"England, have invented certain new and useful Improvements inCarbureters, of which the following is a specification.

My invention has relation to carbureters for internal-combustion enginesand consists in an improved single-jet carbureter wherein the productionof a correctly-proportioned combustible mixture at all engine speeds andunder varying loads and running conditions is realized by regulating thefuelsupply during the opening and closing of the throttle by anarrangement which controls the depression produced by engine suction inthe region of the jet or fuel-orifice.

According to the principal and essential feature of my said invention,the jet or fuel orifice is located within or discharges into a primaryair branch or inductor tube which is open'at one end to the atmospherewhile its other end leads into the main-air passage or mixing chamber ofthe instrument.

Between the said-jet and the main passage,

there is arranged an air-valve or adjustable air-inlet device whichpreferably is operated from or in unison with the main throttle valve,and functions by regulating an ad-' mission of air into the branch-tubeon the engine side of the jet, .to control or govern the depressionwhich can be produced by engine suction over or in the region of thefuel orifice.

This method of and means for controlling the" fuel supply is applicableto various types of carbureter in which a throttle-valve arrangement isused for regulating the admission of explosive mixture to the engine,but

I will first describe, by way of example, the

application of my invention to a single-jet carbureter in which onelever controls the branch and main air supplies and which embodies arotary-plug type of throttlevalve.

. Figure 1 of, the drawings represents a sectional view of such acarbureter embodying Figs. 3 and 4 are sections on the lines as and 00Fig. 1.

Fig. 5 is an elevation of the throttle-operated member of thefuel-controlling device.

Figs. 6 and 7 are longitudinal and transverse sectional views,respectively, of a modification.

In this construction, a is the carbureter livery ends are, by the rotarymovement of the throttle, made to register more or less with the intakeand outlet a a so as to positively control both the admission of themain air supply into the carbureter and the delivery of the mixture tothe engine.

The venturied main passage functions as a controlling choke-tube andalso constitutes a portion of the mixing chamber of the carbureter, andthe areas of the intake and discharge ends of the same are soproportioned in relation to one another that, at all intermediatesettings of the throttle between the full-closed and full-open, enginesuction produces within the said mixingchamber a negative pressure ofsuch a value as will maintain an effective suction on the fuel-supply.

' A branch passage or inductor tube 0 leads to the choke b' of theVenturi passage 5, and is located coaxial with the rotational axis ofthe plug 6. This inductor tube 0- ferred to as the primary-air branch)is internally of a Venturi formation and has a choke at c of aconsiderably smaller area than the choke in the main passage 1), and itis fitted with a fuel-supply nozzle 03 (hereinafter called the jet)whose orifice 03 leads intothe said choke so that fuel is dischargedfrom the jet into the said branch in a direction at right angles to theprimary air stream admitted at the intake 0 The fuel is subjected to theaction of the said air at the point, e. the Venturi chokt 0 where thelatter attains its maxi mum velocity, with the result-that the primaryair is utilized to the best advantage for primarily atomizing the fueland produces within the branch 0, a primary mixture that is dischargedlaterally into the chamber 6 and there mixed with the mainair supplyadmitted at the intake a. The jet orifice d may be regulated by means ofa suitable needle valve 9.

The air-admission valve which controls the fuel supply is arranged onthe engine side of the jet, 6. 0. between the choke c and the outlet 0of the branch 0 into the passage 6 It consists of a system of air ports0 in the tube and an angularly-displaceable sleeve a mounted on theported part of the said tube and formed with a series of openings ecorresponding in number to the ports 0 the said valve-sleeve 6 beingdirectly connected to the throttle member I) by a slot and set-pin e e,in such a way that, while the sleeve is capable of angular adjustmentupon or relative to the throttle within the limits imposed by the lengthof theslot 0 the two members I) and e are normally locked together bythe set-pin e and are rotated as one unit by the throttle-controlmechanism.

The valve-sleeve e is adapted to be set with its openings e in suchrelationship to the air-ports e that movement of the throttle in theopening-up direction will reduce the effective area ofair-passagethrough the openings 0 e, and restrict the admission of airinto the said branch, whereas throttle movement in the contrary (closingdown) direction will enlarge the effective air-passage area at 6 e andadmit an increasing amount of air as the throttle approaches thefull-closed position, with the result that engine suction isenabled toproduce and maintain a relatively greater fuel-inducing depression abovethe et at larger throttle openings (when the inlets of the valve areclosed or only slightly open) than can be produced by the action ofengine suction at small throttle openingswhen the said valve admits airmore freely into the branch on the engine side of the jet. In otherwords, the valve 6, e e ,'is adapted to directly control the depressionand air stream velocity at the jet in synchronism with the opening andclosing of the throttle,.or in such a way that the jet will be caused todeliver the correct amount of fuel for forming the total air admitted byway of the primary and main air intakes, a correctly-proportionedcombustible mixture.

Thefuel-discharging area of the jet orifice is normally a constant ornon-varying factor, inasmuch as the said area is not changed or alteredby or during the movement of the main throttle,- and the said orifice isof such a size as will pass all the fuel required to produce the maximumquantity of mixture for satisfying the demands of the engine when thethrottle is full 0 en at other positions of the throttle in w llCll itfunctions as a factor for controlling engine speed, the action of thevalve cuts down the primary air fiow across the jet and so brings thejet under a reduced fuel-inducing depression.

The fact that the primary air then draws upon a relatively large fuelorifice enables the said air to take up sufficient fuel to produce (withthe main air) the quantity of correctly proportioned mixture requiredfor The openings in the valve sleeve and primary air branch may be madeof any desired shape or size depending on the results required. Forinstance, they ma be made with V-like extensions 6 as in t e exampleshown in the drawing; these extensions being so arranged that during theopening ofthe throttle, they may be utilized to maintain communicationbetween the atmos here and the inductor tube a after the thrott e hasbeen turned through an arc of movement exceeding the diameter of the airports in the sleeve, whereby a certain amount of air'can be admitted atthe valve even when the throttle is fully open.

In a carbureter as above described, when the throttle is opened beyondthe starting position, the resulting acceleration of the 'en gine exertsan increased suction in the dis-. charge end of the primary air branch;but the fact that air can then be freely drawn through the valve 6 e somodifies this suction as to induce a fuel flow suflicient only tocorrectly carburet the air that is then being taken into the carbureter.i Continued opening of the throttle provides for, further engineacceleration, but simultaneously restricts the air admitted through thesleeve valve which enables engine-suction to maintain the relativelygreater depression over the jet for inducing a fuel-flow sufiicient toform a correct mix- -ture with the increasing'quantityof air that isbeing drawn through the main air passage, and as the opening up of thethrottle proceeds, so the sleeve valve may continue to out down the airand augment the depression above the jet until, at the maximum throttleopening, only the extreme V-ends of the sleeve openings are or may be inregister with the branch-tube ports, and the value 126 of' thefuel-inducing depression above the jet is then governed only by enginerevolutions'except when modified by such small quantity of air as canenter the existing port openings of the valve. i

But, by adopting ports of suitable shapes, or byappropriately adjustingthe relative positions'of the sleeves and throttle when regulating thecarbureter, provision may be madeifor entirely closing the valveair-intakes' when or before the throttle is at its maximum opening. Infact, the system admits of the depression above the jet being controlledover the whole or any desired part of the range of throttle'movem'ent,and of the control being timed so that it will come intooperation early or late in such throttle movement, according to the carbureting results required. I

Furthermore, the facts that both the primary and main airpa'ssa'ges areventuried, and that the primary. passage discharges into the mainventuri intermediate the main.

air and mixture-controlling elements of the throttle valve enables thevelocity of the main air'stream to maintain on the primaryair and fuelsupplies, a suction whose value depends upon the volume of main airwhichv the engine is drawing'through the throttle venturi atany givenspeed. And as the jet orifice in the primary air passage is removed fromthe direct influence of engine suction,-

it is impossible (so long as the fuel-orifice area has beenappropriately adjusted to give the correct fuel value to the mixture allalong the scale) for the carbureter to produce an over-rich mixture,even at the highest engine speeds, since the supply of fuel undersuchconditions depends upon the depression that is maintained at thedischarge end of the primary branch by the actual volume of main airthat has to be carbureted.

The invention herein described may also be applied, as shown in F ig s.6 and 7, to a carbureter wherein two linked butterfly valves h, h areused; these valves being I disposed respectively on the atmospheric andengine sides of the discharge end of the primary branch, so that thespace between them constitutes the main mixing chamber.

The linkage '11 coupling the two valves to their control mechanism isalso connected,

such as by the arrangement shown in the said figures, to the movablemember of the atmospheric valve.

In a carbureter embodying a 'maincontrol or throttle. valve other than'of the rotary plug type, the primary air branch may lead into the mainmixing chamber or main-air passage atlany convenient point and in anyconvement direction.

Having now described my invention,

or induction tube having an air intake; a fuel supplyjet located in'said branch; a mam air passage into which the primary 'air branch leads;and an adjustable, valve remote from said air intake adapted toadengines, comprising a primary. air branch mit air into said branch atthe engine side of the jet for controlling thefuel supply.

2. 'A carbureter for" internal combustion engines, comprising a primaryair branch or inductiontube having an air intake; a fuel supply jetlocated in said branch; a

main a1r passage; an adjustable air-admission valve located in saidbranch remote from said air intake; and a throttle valve located in saidmain air passage and connected for simultaneous operation with theair-admission valve so that the latter re- :stricts the admission of airtherethrough during opening movement of the throttle valve, and viceversa.

-3. A single et carbureter, comprlsmg a I main air passage; a throttletherein em bodying two main elements respectively controlling theadmission of main air into the air passage andthe delivery of mixture tothe engine; a primary air induction branch open at one end to theatmosphere and leading at its other end into the main air passageintermediate the two throttle elements; a fuel jet discharging into theprimary air branch; and an adjustableair admission valve located in saidbranch between the delivery end thereof and the fuel jet and connectedfor operation with the throttle elements.

' 4:. A carburetervfor internal combustion engines, comprising a primaryair branch or induction tube; a fuel supply jet located therein; a mainair passage into which the primary air branch leads; an adjustableair-admission valve located in said branch intermediatethe fuel jet andthe main air passage and embodying fixed and'movable v members havingcooperating series of ports;

crating movement with the throttlevalve.

Signed at Birmingham, England, this 28th day of'January A. D. '1919.

- ARTHUR COX.

'fixed member and independently of its opv

